Fluid supported web-drying device



Feb. 14, 1961 M. J. BERLYN FLUID SUPPORTED WEB-DRYING DEVICE 8Sheets-Sheet 1 Filed July 15, 1957 1 I luvsurok M. I BERLYN TraAA XSFeb, 14, 1961 I J. BERLYN 2,971,267

FLUID SUPPORTED WEB-DRYING DEVICE Filed July 15, 1957 8 Sheets-Sheet 2//v VEN TOR M I BERLyN M. J. BERLYN FLUID SUPPORTED WEB-DRYING DEVICEFeb. 14, 1961 8 Sheets-Sheet 3 Filed July 15, 1957 f I Mil/EH70 M. IEmmy/v irmm Hr Feb. 14, 1961 M. J. BERLYN FLUID SUPPORTED WEB-DRYINGDEVICE 8 Sheets-Sheet 4 Filed July 15, 1957 Feb. 14, 1961 M. J. BERLYNFLUID SUPPORTED WEB-DRYING DEVICE 8 $heetsSheet 5 Filed July 15, 1957/NVENTOR MI BERLJN O 7 I 3 Y z I W I Li! v 8 3 M4 WW .w

Feb. 14, 1961 M. J. BERLYN FLUID SUPPORTED WEB-DRYING DEVICE aSheets-Sheet 6 Filed July 15, 1957 /NVENTOR MI BERLyN Feb. 14, 1961 M.J. BERLYN 2,971,267

FLUID SUPPORTED WEB-DRYING DEVICE Filed July 15, 1957 8 Sheets-Sheet '71 7 4 1 1- /NVENTOR M J. BERLyN Feb. 14, 1961 M. J. BERLYN FLUIDSUPPORTED WEB-DRYING DEVICE 8 Sheets-Sheet 8 Filed July 15, 1957//VVENTIOR MI Bmzyu United States Patent '0 FLUID SUPPORTED WEB-DRYINGDEVICE Martin J. Berlyn, Montreal, Quebec, Canada, assignor to DominionEngineering Works Limited, Montreal, Quebec, Canada Filed July 15, 1957,Ser. No. 671,866

11 Claims. (Cl. 334-456) This invention has reference to the drying ofthin webs during the course of manufacture and is more particularlydirected to the problem of drying a continuous web of paper, but it isby no means excluded from other applications.

around the peripheries of a series of revolving steamheated cylindersthe web is pressed into contact with the cylinder surfaces by tensionedfelts. The efliciency of heat transfer from steam to paper is low. Thearrangement is also bulky and costly.

At lineal speeds considerably higher than those of contemporary highspeed paper machines the conventional type of dryer would be even morecostly and bulky than it is at present. Cylinder diameters would have tobe increased in order to avoid dynamic malfunctioning at the higherlineal speed and, unless the diameter were to be increasedsubstantially, a greater number of cylinders would have to be employedin order to satisfy the time function of the evaporating process.

The physical arrangement and the geometric configuration of contemporarydryers do not lend themselves well to provision of efiicient means forremoval from the neighbourhood of the web of the moisture released fromit, and the hot and humid air surrounding such dryers constitutes anoccupational hardship for the operating personnel.

In this invention, hot air is flowed over both sides of the web of papersimultaneously. The direction of air 1 flow in normal operation iscounter to the direction of motion of the web.

The moisture-laden air which has been passed over the Web is rejectedthrough heat-exchanging means in which incoming fresh air is preheated.

Thestream of hot air for each side of the web is circulated by aseparate blower. A pair of blowers, one

such blowers suitably ducted and driven at the same speed acts as a flowdivider. This device maintains the web central in its passage throughthe dryer casings While the streams of hot air pass on either side ofthe web in a direction counter to the motion of the web.

By flowing the streams of hot air counter to the direction of motion ofthe web two desirable objects are achieved; the hottest and driest airsweeps the hottest and driest part of the web while the cooler andmoister air sweeps the cooler and wetter part of the web, thus providingthe most uniform rate of drying, and the resultant high velocity of thehot air relative to the web is favourable to the removal from the websurfaces of the water vapour which has been released from them.

2,971,267 Patented Feb. .14, 1961 Although the hot air in normaloperation passes through the casings counter to the direction of motionof the web, arrangements are provided, as will be explained hereinafter,to pass the hot air through the casings in the direction of motion ofthe web when starting a run, or when restarting after a break. This isto say that hot air in motion is employed as a vehicle to carry the webthrough the casings when starting up.

This hot air, to which motion has been imparted by blowers, is atsubstantially atmospheric pressure. It is employed as a vehicle only forthe straight long vertical runs of the web, alternately downwards andupwards,

through successive elements of the dryer assembly.

For changing the course of the web, as when transferring it from onecasing element to the next in series, another air system is employed.This other system uses a relatively small amount of air which is fedfrom a source of compressed air at relatively high pressure and releasedthrough suitably located jets as will be hereinafter explained. Thecompressed air system is employed only when the hot air is being blownthrough the dryer casings in the direction of motion of the web, as whenthreading the web through the dryer at starting; it is shut off andinoperative when the hot air is being blown through the dryer casingscounter to the direction of motion of the web, as in the steady-statedrying operation. The compressed air system is also responsible forsteering the web through certain restricted passages in the dryercasings and for directing it into the nips of pairs of rolls; inaddition, it is employed for lifting the web from the surfaces of rollsto which it clings instead of peeling off tangentially as necessary forsuccessful threading of the web through the dryer assembly.

In transfer from the outlet end of one dryer casing element to the inletend of the next dryer casing element in series, the web is carried overthe periphery of a cylindrical roll, which will be referred to as aturning roll. Associated with each turning roll is another roll whichwill be referred to hereinafter as a presser roll. While the web ischanging its direction through between leaving one dryer casing elementand entering the next in series, and is riding around the periphery of aturning roll, the associated presser roll rides firmly on the side ofthe web remote from the turning roll; at each transfer from one dryercasing element to the next in series, therefore, the web passes throughthe nip between a turning roll and its associated presser roll. Thereason for provision of a presser roll for each turning roll is asfollows: when moisture is removed from a wet web by sweeping itssurfaces with hot air, the web becomes drier at its surfaces than at themiddle of its thickness but, by squeezing the web in a roll nip themoisture from the middle of its thickness is forced towards thesurfaces; this squeezing between rolls therefore, is a device forcausing moisture to migrate from the inside of the web to its surfacesthereby giving hot air direct access to web moisture when the web passesthrough a dryer casing element immediately following its exit from aroll nip.

An object of this invention is to provide a highspeed web-drying devicefor operation at web speeds in excess of contemporary practice.

Another object is to provide a web-drying device which is smaller andless costly than those commonly in use.

Another object is to provide a web-drying device having a higher thermalefficiency than those commonly employed in the industry.

Another object is to provide a web-drying device requiring a lower powerinput than that demanded by present-day dryers.

Another object is to provide a web-drying device which does not employfelts.

Another object is to provide a web-drying device which elements of thedryer.

will not release excessive heat into the machine-room in which it ishoused.

Another object is to provide a web-drying device which does not employrotary steam joints.

Another object is to provide a web-dryerin which the rolls contain nomoisture.

Another object is to provide a web-drying device in which the rolls arenot subjected to internal fluid pressure.

Another object is to provide improved means for leading a web initiallythrough all the elements of a webdrying device, for starting a run, orfor restarting following a break in the web.

Figs. 1A, 1B and 1C conjointly show a longitudinal vertical mediansection through a series of nine typical All elements are similar but,throughout the length of the dryer, alternate casing elements areinverted to accommodate thereversal of direction of motion of'the webinsuccessive elements.

Fig. 2 shows a partial end elevation of the group of dryer elements.

Fig. 3 is a front elevation of the group of three dryer casing elementsat the wet end of the dryer, showing more detail of construction than isdisclosed in Fig. 1A.

Fig. 4 is an end elevation of Fig. 3 and shows the external ducting andpiping associated with a group of three dryer casing elements.

Fig. 5 is a rear elevation of the group of three dryer casing elementsat the wet end of the dryer and shows theexternal ducting, valving, andpiping associated with portion of Fig. 7.

Fig. is a partial section, on an enlarged scale, through the upper endof the second, or any even-numbered, dryer casing element; it is in aplane normal to the web, as indicated at 19-11; on Fig. 11. This is theweb-exit end of a dryer casing element.

Fig. 11 is a partial vertical median section, in the plane of the web,through the portion of a dryer casing element shown in Fig. 10, asindicated at 11--11 in Fig. 10.

'Fig. 12 is, on an enlarged scale, a partial section in a plane normalto the Web, through a portion of the dryer casing shown in Fig. 10.

Fig. 13 is a section through 13-13 of Fig. 12. Fig. 14 is an enlargedsection through the same portion of a dryer casing as shown in the upperright-hand "part of Fig. 7.

Fig. is a section through15-15 of Fig.3.

Referring now more particularly to Figs. 1A, 1B and 1C, it will be seenthat all casing elements are similar but, throughout the length of thedryer, alternate elements are inverted to accommodate the reversal ofweb direction in successive elements.

As shown, the nine dryer elements are, insofar as their associatedducting is concerned, subdivided into groups of three.

The web 1 is passed successively through the entire series of dryercasings 2. Atmospheric air entering at 'duct 3 (Fig. 1C) passes througheconomizer 4 which it leaves by way of duct 5. Duct 5 is connected withmanifold 6 from which branch ducts 7 (Fig. 1B) lead to air heaters 8.From air heaters 8 hot air leaves by way of ducts 9 from which branchducts 10 convey air to blowers 11. As shown, each group of three dryerelements 2 is provided with a pair of blowers 11 driven by a commonmotor 12. From blowers 11 hot air passes through ducts .13 to four-wayvalves 14.

In Figs. 1A, 1B and 10 the four-way valves 14 are all shown with movablevalve members 15 in the position in which they are held during theoperation of drying web 1; in steady-state drying of web 1 the hot airleaving blowers 11 by way of ducts 13 is directed by four-way valves 14to dryer casings 2 in such a manner that the direction of the hot airthrough dryer casings 2 is counter to the direction of motion of web 1.Considering the steady-state web-drying operation, with movable valvemembers 15 oriented as shown solid in Fig. 1, hot air passes from valves14 through ducts 22 to the ends of casings 2 from which web 1 isleaving. The hot air passes through casing 2 in a direction counter toweb 1 and leaves the first casing of a group of three by way of jumperducts 23. Hot air from jumper ducts 23 enters the next element of thegroup of three dryer casings 2 and passes through this dryer casing 2 ina direction counter to the motion of web 1. Leaving this second casingelement 2 of the group of three the hot air passes through another pairof jumper ducts 23 and enters the third element of the group of threedryer casings 2. Passing through this third element of dryer casing 2,again in a direction counter to the motion of web 1, the hot air leavesthis third element of dryer casing 2 by way of ducts 24 which lead tofour-way valves 14. The hot air leaves four-way valves 14 by way ofbranch ducts 16 which lead it to duct 17 and thence it flows by way ofduct 18 to manifold 19. Fromrnanifold '19 it passes through duct 20 toeconomizer 4. On leaving economizer 4 the air is rejected to wastethrough outlet duct 21.

Hot air leaving the dryer assembly by way of manifold 19 is not onlyloaded with moisture but it is hotter than the atmospheric air enteringeconomizer 4 by way of duct 3. In economizer t, therefore, the air andwater vapour from manifold 19 give up heat to the fresh air entering thesystem through duct 3 and this air, which leaves economizer 4'by way ofduct 5 and enters the dryer system by way of manifold 6, is preheated bywaste heat from the spent air and water vapour from manifold 19.

When starting a run, or when restarting after a break, the movable valvemembers 15 are turned through and assume the orientation as shown dottedat 15' in Fig. 1. With the movable valve members 15 oriented as shown at15' the hot air leaving blowers 11 by way of ducts 13 is directed intoducts 24 which now feed air to the ends of dryer casings 2 at which web1 enters dryer casings 2. The heated air is then driven through dryercasings 2 in the direction of motion of web 1 and, after passing throughjumper ducts 23 in the opposite direction to that in which it flowedduring steady state drying, the air leaves the third element of eachgroup of three dryer casings 2 by way of ducts 22 and leaves four-wayvalves 14 by way of ducts 16 and 17 and thence by way of branch ducts18, manifold 19 and duct 20 to economizer 4 from which it is rejected towaste via duct 21.

The arrangement of four-way valves 14, as shown in Figs. 1A, 1B and 1C,is a convenient device for reversing the direction of the air flowthrough dryer casings 2. Flowing the air through dryer casings 2 in thedirection of motion of web 1 makes possible the threading of web 1through the dryer casings 2, and flowing the air through dryer casings 2in the direction counter to the motion of the web provides the conditionrequired for efiicient heat exchange between the hot air and the web 1and for effective removal of the moisture released from the surfaces ofthe web.

With reference now to Figs. 3 to 15, consider conditions when the web isbeing led into and through the dryer at the start of a run.

As indicated in Fig. 5 the movable valve members 15' of four-way valves14 are so oriented that the hot air from ducts 13 will be driven throughcasings 2 in the direction of motion of web 1.

Air at relatively high pressure from a source of cornpressedair is fedby manifolds 46 to branchpipes 47,

'48, 49, so, 51 and 52 (best shown in Fig; which lead to ports 53 (Figs.7 and 9), 54 (Figs. 7 and 14), 55 and 56 (Figs. 10 and 12), 57 and58(Figs. 7 and 14) respectively.

Ports 53 feed air jets 29 and 60 (Fig. 9). Ports 54 feed jets 30 and 61(Fig. 14). .Ports 55 feed jets 42 and manifolds 38; manifolds 38 feedjets 39 (Figs. 10, 11 and 12). Ports 56 feed manifolds 38 which in turnfeed jets 39 (Fig.12). Ports 57 feed jets 32 and 59; ports 58 feed jets59 (Figs. 7 and 14).

Web 1 entering the dryer by way of guide rolls is passed by air guide 26into the nip between presser roll '27 and turning roll 28 (Figs. 3, 7and 9).

ing roll 23, if web 1 should cling to thesurface of presser roll 27 itis lifted off by jets 61 (Fig. 14) and momentum carries it into the gapbetween the periphery of turning roll 28 and air guide 31. Air from jets30 deflects web 1 towards the periphery of turning roll 28 and preventscontact of web 1 with the surface of air guide 31; it also drives web 1towards the entrance to casing2. 4

, If web 1 clings to the surface of turning roll 28 it is lifted otf byjets 32 and momentum, aided by air from jets 30, carries it into theentry-throat of casing 2 where it is caught by jets 5 9 and 59' whichthen steer and propel it into the portion of easing 2 generallyindicated by (Figs. 7 and 14).

Two streams of hot air are directed by movable valve members 15 offour-way valves 14 along ducts 24 (Figs. 4 and 5) to casing elbows 33 inwhich turning vanes 34 (Figs. 7 and 8) steer them to turning vanes 36(Figs. 7 and 14) which direct them through the long vertical run of thefirst of a group of three casings 2.

The leading end of web 1, having been propelled by jets 59 and 59' intothe portion of casing 2 generally indicated by 35 (Figs. 7 and 14) iscaught in the two streams of hot air from turning vanes 36 (Figs. 7 and14) and is carried through the long vertical run of the first of a groupof three casings 2.

At the Web-exit end of casing 2 in the region generally indicated by thetwo streams of hot air leave the long vertical run of casing 2 by way ofturning vanes 37 (Figs. 3, 1t 11, 12 and 13) thence the two streams ofair pass through casing elbows 33 at the web-exit end of the first of agroup of three casings 2 into jumper ducts 23 (Figs. 4, 5, 6 and 15).

Web 1 entering the web-exit zone of easing 2 as generally indicated by40 is deprived of the driving force of the two streams of hot air asthey leave casing 2 by way of turning vanes 37 but now web 1 is caughtby the streams of high-pressure air issuing from jets 39 and 39 inmanifolds 38 and 38 respectively and driven to and through the web exitthroat of easing 2 (Figs. 10, 11,12 and 13). Air from jets 42 deflectsweb 1 from contact with air guide 41 (Figs. 3, 10 and 12) and towardsthe surface of turning roll 28.

Air from the jets 39 and 42 escapes by way of ports 43 (Figs. 10 and 12)and pipes 44 (Figs. 3, 4 and 5) and is returned to casing 2 via bosses45 (Figs. 4 and 5). Air from jets 3'? escapes by way of ports 62 (Figs.10 and 12) and returns to casing 2 which is at a lower pressure.

When web 1 leaves the nip of presser roll 27 and turning roll 28 itprogresses through subsequent casings 2 in exactly the manner describedabove with reference to its passage into, through, and out of the firstcasing 2 of the series. As mentioned earlier, the web passes When theweb has been vertically downwards in the odd-numbered casings 2 andvertically upwards in the even-numbered casings 2. In principle it couldbe vice-versa but the odd-down evenup arrangement is preferred as beingmore convenient.

Hot air passes from the web-exit end of the first of three casings 2 tothe web-entry end of the second of three casings 2 by way of jumperducts 23 (Figs. 4, 5 and In the same manner the hot air passes from theweb-exit end of the second of three casings 2 to the web- 'entry end ofthe third of three casings 2.

On leaving the web-exit end of the third of threecasings 2 the hot airpasses through ducts 22 (Figs. 4 and 5) by way of four-way valves 14 toducts 16 and, via ducts 17, branch ducts 18, manifold 19, and duct 20 toeconomizer 4.

threaded through the entire dryer assembly, which may consist of, say,forty-five dryer casings 2 in fifteen groups of three, the direction offlow of the hot airthrough the casings 2 is reversed, preferably in onethree-casing group at a time, by turning the movable valve members 15'of four-way valves "14, a coupled pair at a time, through so that theyassume the positions which direct the hot air through casings 2 in thedirection counter to the motion of web 1. .Also, as soonas the web hasbeen threaded through 'the entire dryer assembly, the compressed airsupply to manifolds 46 (Figs. 3, 4 and 5) is turned oif.

The turning rolls 28 constitute mechanical web propelling means formoving the web through the various elements of the dryer during the webdrying operation. These rolls are driven, by any suitable drive means,at speeds controlled to maintain proper tension in the web and to passit through the dryer at the desired rate. The presser rolls 27 arefreely journalled rolls whose sole function is to exert pressure on theweb to force moisture from the interior to the surfaces of the web.These turning and presser rolls contain no moisture and are free ofinternal pressure.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. Web drying apparatus adapted to thread the web therethrough beforesubjecting it to counter-current air drying, comprising means definingan elongated drying chamber having an opening at each end for thepassage of a vertically aligned web, means for guiding the verticallyaligned web through each of the end openings, and means for selectivelyadmitting two streams of air at alternate ends of the chamber to flowlongitudinal thereof in contact with opposite sides of the web, saidlast-named means comprising duct means for supplying the air streams andcommunicating with the chamber at oppositely disposed ports adjacenteach end opening in the chamber, means associated with the duct meansfor dividing the air supply into two equal streams and selectivelyintroducing the equal streams through the ports at alternate ends of thechamber, and means associated with the ports for directing the equal airstreams into engagement with opposite sides of the web in a directioninclined toward the opposite end of the chamber.

2. Web drying apparatus according to claim 1 wherein the air supplydividing and introducing means associated with the duct means comprisesa pair of blowers connected with common driving means and valve meansdisposed in the duct means intermediate the pair of blowers and theports.

3. Web drying apparatus according to claim 2 wherein the duct meansincludes a pair of ducts each of which communicates with one of theports at each end of the chamber and each of the blowers is associatedwith one of the pair of ducts, and the valve means includes a valvedisposed in each duct intermediate the blower associated therewith andthe ports with which it communicates.

4. Web drying apparatus according to claim 3 further 7 comprising-heattransfer means associatedwiththe duct means and with which each of thepair of ducts communicates, each of the valves being adapted to diverteflluent air from the chamber to the heat transfer means to preheat theair supply to the blowers.

5. Web drying apparatus according to claim 1 wherein the air streamdirecting means associated with the ports comprises a series of vanes sodisposed in each port as; to direct the air stream introducedtherethrough in a direction inclined towards the opposite end of thechamber.

6. Web drying apparatus according to claim 1 wherein the Web'guidingmeans comprises air jets disposed adjacent the inside peripheral portionof each end opening to operatively engage the web at its sides.

7. Web drying apparatus according to claim 6 wherein the air jets aremounted in manifold extending transverse the mouth of theports adjacentthe end opening.

8. Web drying apparatus according to claim 1 wherein the web guidingmeanscomprises a pair of rollers so disposed adjacent each end openingas to form a nip for the web and means: disposed between the nip of therollers and the adjacent end opening for guiding the web therebetween.

9. Web drying apparatus according to claim 8,wherein the meansforguiding the web between the nip of the rollers. and the adjacent endopening includes air jets disposed tooperatively engage the web at itssides.

10. Web drying apparatus adapted to thread thetweb therethrough beforesubjecting it to counter-current air drying, comprising means defining aplurality of parallel, elongated drying chambers each having an openingat each end for the passage of a vertically aligned web, means forguiding the web through each of the end openings, means for guiding theweb between adjacent selectively admitting-two streams of air atalternate ends of each chamber to flow longitudinal thereof in contactwith opposite sides of the web, said last-named means comprising ductmeans for supplying the air streams and communicating with the chamberat oppositely disposed ports adjacent each end opening in the chamber,means associated with the duct means for dividing the air supply intotwo equal streams and selectively introducing the equal streams throughthe ports at alternate ends of the chamber, and means associated withthe ports for directing the equal air streams into engagement withopposite sides of the web in a direction inclined toward the oppositeend of; the chamber.

11. Web drying apparatus according to claim 10 wherein the means forguiding the web between the adjacent end openings of the pair ofchambers includes a pair of rollers so disposed between the adjacent endopenings as to form a nip for the web, means defining a curvilinearpassage for the web with the cylindrical surface of one of the rollersbetween each of the adjacent end openings and the nip of the rollers,and air jets disposed to operatively engage the web at its sides andurge it through the passage between each of the adjacent end openingsand the nip of the rollers.

References Cited in the file of this patent UNITED STATES PATENTS1,523,081 Ramsdell Jan. 13, 1925 1,556,057 Wheller Oct. 6, 19251,847,915 Bailey Mar. 1, 1932 2,012,115 Woodruif Aug. 20, 1935 2,037,806Little Apr. 21, 1936 2,560,341 Ham et a1. July 10, 1951

